Posts tagged signal
Today we made some serious progress in creating an initial IP stream using a few odd bits of kit lying around room 906. The bodged system myself and Scott came up with consisted of:
- 1 x Cisco DME 1000 (Stream Encoding)
- 1 x Sound Desk (Tone Generation)
- 1 x Composite Signal Generator
- 1 x Picture Monitor (Live View)
- 2 x MacBook Pro Laptops (Stream ReEncoding and Viewing)
Today, has been an eventful day mainly due to the snow that has been falling constantly for the last 24 hours. This morning there was only a light dusting of snow on the ground, so I risked it and went to uni as usual, no problems getting in. It was whilst I was at uni, things started to go bad. The snow just kept falling and falling, which i knew was bad right from the start, even though it wasn’t settling at North Greenwich.
This morning we had a practical tv systems and signals lecture with John Palmer. We looked into termination of video signals, and why it was important. which was an interesting lecture. and it surprised alot of us, how much the signal changed based on if it was terminate or unterminated.
At the end of this lecture, the snow was still falling and I was now dreading trying to get home.
Another Electronics Practical in the afternoon, and the snow was still falling, by this time, my dad had phoned me to say we now had nearly a foot at Petts Wood, and that it will be hard trying to get home.
I finally left uni at 5pm, and got to Lewisham via the Jubilee Line and DLR with no Problems. Lewisham had still only 2-3 inches of snow and trains were running ok, into London. MY train arrived about 10-minuets late and was said to be fast to Orpington, which was fine for me, just meant a slightly longer walk back.
We Pulled out of Lewisham and moved slowly down to Hither Green, where we stopped and the opened the doors. This wouldn’t have happened if we had been the true fast service that they had said in Lewisham. We had stopped because there were 5 other trains in front of us trying to reach the South East, all being blocked by one train that had broken down at Petts Wood.
After 3 hours of very slow moving and long waits at stations we finally made it to Petts Wood, the snow is in deed over a foot deep, and there are only two lines out of the usual 4 the could just about be used. Walking back from Petts wood station was just as dangerous, with next to no grip on the compacted snow.
I don’t think, I’ll be going to uni anytime soon.
Continuing on from the basics we learnt in the first few lectures, we moved on to some basic analogue circuits, including creating a Hi-pass and Low-Pass filter. These filters are both very simple, yet they provide crucial functionality in many everyday appliances. A good example of this is the Phone it has a 3KHz Hi-Pass Filter in it, creating the distinctive sound you hear. A Mid-Pass Filter is another extremely common one, particularly in broadcasting. Used mainly in TV tuners, to decipher one signal from the next. They are used for this purpose as they can be set to allow a very small frequency range through at a time, useful for splitting the hundreds of signals sent over FreeView.
TV Systems & Signals
TV Systems and Signals, was unfortunately canceled today due to unforeseen circumstances.
Another day, another circus Session this time we were learning about location sound. this is what i wrote about it for my Circus Report:
Locations sound works hand in hand with location camera’s providing additional sound capabilities to the single camera, for example an interview situation that required two personal mic’s could be mixed together before being fed to the camera as stereo or mono line level mix. Location mixers often have 2-4 inputs and can either mix in stereo or dual mono. Location mixers normally have better Microphone pre-amps than Camera’s, which in turn provides better sound quality, as the mixer is outputting at line level (0db) and the camera won’t apply any more amplification to the signal.
Some microphones require batteries or phantom power (+48v) to operate; these mic’s are a form of capacitor mic’s are much more sensitive than standard dynamic mic’s that don’t require power to operate. Most cameras and mixers can supply phantom power to these microphones.
When setting up for a shoot, you can use the tone that the mixer is supplying to the camera to help setup the record levels on the camera. Tone should be set just below the 0db mark as this allows some “head room” before the camera starts to clip the signal should you go above the tone volume.
Optical Fibre Links
Today we looked at optical fibre links and how they now power the internet age that is now upon us. The amazing power of fibre is slowly being understood with new theoretical limits being constantly found, the current tested theoretical limit could handle the worlds current internet and phone traffic, and more in a single fibre.
Fibre’s are the back bone the UK broadcast industry, as they link all the Studio Centers with the 1000+ Transmission sites in the UK. The Fibre links are mission critical for all Analogue and Freeview transmission, as they provide the 17 Main and 1000 “Fill” UHF Transmitters, with the signal to broadcast.